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The Story of Germ Life by H. W. (Herbert William) Conn
page 18 of 171 (10%)
enables them to resist almost any amount of drying, a high degree
of heat, and many other adverse conditions. Commonly the spores
break out of the rod, and the rod producing them dies, although
sometimes the rod may continue its activity even after the spores
have been produced.

Arthrogenous spores (?).--Certain species of bacteria do not
produce spores as just described, but may give rise to bodies that
are sometimes called arthrospores. These bodies are formed as
short segments of rods. A long rod may sometimes break up into
several short rounded elements, which are clear and appear to have
a somewhat increased power of resisting adverse conditions. The
same may happen among the spherical forms, which only in rare
instances form endogenous spores. Among the spheres which form a
chain of streptococci some may occasionally be slightly different
from the rest. They are a little larger, and have been thought to
have an increased resisting power like that of true spores (Fig.
13 b). It is quite doubtful, however, whether it is proper to
regard these bodies as spores. There is no good evidence that they
have any special resisting power to heat like endogenous spores,
and bacteriologists in general are inclined to regard them simply
as resting cells. The term arthrospores has been given to them to
indicate that they are formed as joints or segments, and this term
may be a convenient one to retain although the bodies in question
are not true spores.

Still a different method of spore formation occurs in a few
peculiar bacteria. In this case (Fig. 14) the protoplasm in the
large thread breaks into many minute spherical bodies, which
finally find exit. The spores thus formed may not be all alike,
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